The effect of temperature and time on the population dynamics of Meloidogyne chitwoodi in potato tubers during storage

This experiment was carried out to assess the population dynamics of Meloidogyne chitwoodi in tubers under different storage conditions used in The Netherlands. Infected tubers were produced by growing the susceptible cv. Désirée in 100, 10 kg pots at a density (Pi) of = 12 J2 g dry soil- 1. Infected tubers of all pots were combined and sorted into classes based on their tuber-knot index. Thirteen batches of infected tubers were composed of equal amounts of tubers from each index. The infected tubers were stored at 98% relative humidity at temperatures of 4, 8 and 12 oC and nematode numbers were assessed after 0, 2, 4, 6 and 8 months storage time. After hardening, peeling and mixing of the skins, replications were placed in the spray-mist chamber for 7 weeks to extract the juveniles. The logistic model was fitted to the cumulative hatch to follow the hatching process of M. chitwoodi from the peel and the estimated maximum cumulative hatch was used to evaluate the treatments. Both storage temperature and time influenced the population dynamics of M. chitwoodi in potato tubers. Storage temperatures of 4 and 8o C reduced populations of M. chitwoodi up to 96% and 89% after 8 months of storage. However, at 12oC the population density remained at the same level over time. Recovered juveniles of M. chitwoodi from tubers after 6 and 8 months of storage, at all three temperatures, proved to be still infective on the susceptible cv. Désirée.